Here is a round up of all the conspiracy theories – and likely scenarios –
involving missing Malaysia Airlines flight MH 370

This seems to be the theory that investigators are focusing on. The plane's tracking devices were switched off, and it swerved off course from its intended Kuala Lumpur – Beijing route. But we don't know why any of the Malaysia Airlines employees would want to do this.

An American congressman, Peter King, even suggested that the pilots could have crashed the plane as suicide, so their families could claim their life insurance pay outs.

Terrorism from pilot

Captain Zaharie Ahmed Shah, 53, was an aviation fanatic who built a flight simulator in his home. Police have removed the simulator from his house, and discovered several routes that he rehearsed.

He was related to opposition leader Anwar Ibrahim, and attended the court hearing just hours before the flight, in which Ibrahim was sentenced to prison.

Furthermore, Capt Shah's wife and three children moved out of the house the day before Flight MH 370 took off.

But friends and colleagues remain adamant that Capt Shah has not been involved in any conspiracy.

Terrorism from co-pilot

Fariq Abdul Hamid, 27, is seen as a less likely conspirator.

He was due to marry his long-term girlfriend – a fellow pilot, from Air Asia – and said to be a mild-mannered man who occasionally attended his local mosque, and was a keen car enthusiast.

Hijack by passenger

This theory is always the foremost explanation for a hijacking scenario. But China on Tuesday ruled out any of their citizens – who made up just over half of all passengers.

Two Iranians travelling on stolen passports are now thought to be asylum seekers, rather than terrorists.

Mechanical failure

This was, understandably, the initial assumption.

But America quickly said that its satellites had detected no explosion, and neither Rolls-Royce – the engine manufacturers – nor Boeing, the aircraft designers, seemed to think there had been a mechanical failure.

Fire in the cockpit

This theory was expounded by Chris Goodfellow, a pilot with 20 years experience.

He suggests that a fire caused by the warm evening, heavy aircraft, and possible friction on take off knocked out the radar. He thinks the pilot then looped back to try and find the closest runway, but was overcome by smoke - allowing the plane to fly on, on autopilot.

Hypoxia

Hypoxia is the condition when the body does not receive enough oxygen. It can cause an increase in heart rate, edemas, confusion, headaches and eventually unconsciousness.

It can occur at high altitude and also while scuba diving.

One theory is that the oxygen supply failed, leaving the plane pilotless and causing all the passengers to fall unconscious.

'Cyber hijack'

One of the more outlandish suggestions: was the plane hijacked remotely? Would this be possible, using a mobile phone or a USB stick?

Experts say it is highly unlikely.

Attempted 9/11 style attack

This was another early assumption. When the plane was discovered to have swung back, passing near the Petronas Towers – the tallest twin buildings in the world – the parallels with the September 11 attacks were obvious.

But authorities say they have no evidence to support talk of an international plot.

Diverted to Somalia

Reported sightings of a "low-flying jet" in the Maldives have led some to speculate that the pilot was heading to Somalia, either of his own accord or under coercion.

Somalia, with weak central government, is one place where the plane could have landed without following standard protocols.

But even so, it seems unlikely we would have not heard about it by now.

Taliban conspiracy

Did the plane attempt to land in Taliban-held territory in Afghanistan or Pakistan?

This would be theoretically possible – but is still seen as unlikely.

Indeed, a Taliban commander said he "wished" that they had been involved.